This invention regards a post processor that receives the sheets, onto which the image has already been recorded and which are discharged from image formation machines, such as printers, copiers, facsimile machines, and printing presses, and fed into the post processor, and that discharge the sheets after the necessary processing inside.
There have been, in the prior art, post processors that take the sheets onto which the image has already been recorded and which are discharged from the image formation machines such as printers and copiers and that discharge the sheets after the necessary processing such as sorting, inverting and punching and/or binding inside the post processor.
By incorporating a perforator or punch into the post processor, sheets can be perforated or punched. In order to do so, the post processor takes sheets in completely and stops them, and the perforator is placed where its perforation point meets the stopped sheet. However, since this structure requires a large space for taking and stopping the sheets, the size of the post processor may be enlarged.
On the other hand, if the post processor stops sheets before completely taking them inside, that is, to stop them while the image formation machine holds the latter half of the sheets, the size of the post processor can be minimized. However, in that case, since the control of the image formation machine needs to be changed to stop the sheets, the cost of initializing a post processor increases and it cannot be used for the existing image formation machines.
The post processor with a sheet inverting function can rotate sheets half way without damaging them. Upon such basic performance as a premise, it is desirable for the post processor to be very compact, not to require too much installation space and to maintain low cost.
Therefore, the post processor conventionally receives the sheets discharged from the image formation machine at the specified speed and discharges the sheets after the processing such as binding. This requires the processing capability with the speed not to disturb the sheet output timing of the image formation machine.
In order to do so, the transporting speed of the sheets inside of the post processor is set up to be higher than the speed of the image formation machine to create necessary processing time. However, since the sheet transporting structure in the post processor is typically designed to have several feed rollers placed at intervals that are shorter than the length of the sheets, the transporting speed of all sending rollers needs to be generalized. Therefore, it has been considered difficult to set up the transporting speed in the post processor higher than the sheet infeed speed of the image formation machine.
In view of the above, an object of the present invention is to provide a post processor that is compact and inexpensive while being equipped with a post processing function and that can be installed in conjunction with the existing image formation machines.
In order to achieve the above objective, this invention provides the post processor for an image formation machine that receives the sheets discharged from the image formation machine with infeed means and which discharges them after the necessary processing inside, wherein gate means to stop the leading edge of moving sheets in the middle of the sheet feed path, and that locates the automatic punch to punch holes in the specified position close to the front edge of the temporarily stopped sheets, and has a free space to enable the sheets to bend in front of the automatic punch.
The above post processor stops the front end of the sheets by the gate means and punches the sheets by the punch means while the image formation machine continues to feed sheets regardless of the functions of the post processor. The latter half of the sheet is sent toward the post processor even during the punching or other post processing. Therefore, the middle portion of the sheet bends in a loop and the sheet escapes into a free space since only the front end of the sheet is stopped by the gate means during the punching process.
Then, the post processor restarts feeding sheets after the completion of the punching process.
The feed rollers can be established in the middle of the sheet feed path and can be used as the aforementioned gate means by turning on and off the feed rollers. By doing so, it is cost effective because the gate means does not have to be separately provided.
The above feed rollers should be structured with two driving rollers facing each other. If the feed rollers are formed by two driving rollers like this, the resistance increases while the sending rollers stop, and the rollers become less likely to idle when the sheets contact the stopped rollers causing the sheets to stop at a certain position.
In order to achieve the above purpose, this invention provides a post processor for an image formation machine that has the feed path to take the sheets discharged from the image formation machine at the lead edge, to pass them through the machine, and to discharge them from the output from the post processor.
An inclined tray is located in the area directly underneath the feed path to incline the leading edge of the sheets downwardly to a sheet stopper on the lower end of the tray, a sheet transporting means to discharge the sheets placed on the inclined tray to an output portion of the post processor, a divergent feed path to feed the sheets from the middle of the aforementioned feed path onto the inclined tray, and a diverter located at the connection of the aforementioned feed path and the diverging path to alternatively switch the flow path to the output path or the diverging path, and that sets up the angle of the sheet and the higher side of the inclined tray to be acute when the sheets sent from the aforementioned diverging path move from the higher side to the lower side of the tray by being guided by the inclination of the inclined tray and stop when they hit the sheet stopper.
The above post processor receives the sheets discharged from the image formation machine at the lead end, passes them through the machine and discharges them from the output when the diverter opens the bypass path. On the other hand, when the diverter opens the diverging path, the sheets discharged from the image formation machine enter into the infeed path and flow onto the inclined tray from the bypass path through the diverging path. Since the angle of the sheet and the higher side of the inclined tray is set up to be acute when the sheets fed from the diverging path touch the inclined tray, the sheets entering into the inclined tray from the diverging path flow naturally from the higher end to the lower end along the inclination of the inclined tray and stop when they hit the sheet stopper. The sheets are reversed or inverted at this stage. Then, the sheet transporting means activates to push back and discharge the sheets placed on the top of the inclined tray.
The diverging feed means should be formed to force the sheets out toward the inclined tray in the aforementioned diverging path and to let the front end of the sheets reach the sheet stopper of the inclined tray before the diverging feed means releases the rear end of the sheets. By doing so, the front end of the sheets accurately reaches at the sheet stopper at high speed and the edges of the sheets can be aligned nicely. In a natural dropping method, first it takes time for the sheets to reach the sheet stopper and to stabilize themselves, and the sheets may stop in the middle of the process and the lead edges do not match.
A runner should be incorporated into a part of the diverging feed means and kick out the rear of the sheets onto the inclined tray. By doing so, high speed processing can be done without letting the trailing end of the sheet touch the leading end of the following sheet.
The punch should be located in front of the aforementioned diverter and enables punching the sheets between the infeed portion of the paper path and the diverter. By doing so, the punch can perforate both the sheets that passes through the feed path and the sheets that are supplied to the inclined tray in an inverted condition.
A cut off portion can be formed in a part of the aforementioned inclined tray and a stapler can be established to fit the cut off portion. By doing so, the sheets placed on the inclined tray according to the page number by inverting them on the tray can be bound by the stapler.
A tray guide should be formed above the aforementioned inclined tray and a deformed portion should be formed in either or both the inclined tray and/or the tray guide to correspond to the cut off portion. Thus, the gap between them becomes narrower by focusing around the cut off portion. By doing so, the stapler can easily bind the sheets because the thickness of a batch of sheets is tightened and reduced by the deformed portions. Since the deformed portions are partial and the resistance to the sheet decreases, the sheets can be inserted into or discharged from the deformed portions smoothly.
The post processor has the one way clutch mechanism associated with the infeed rollers to feed the sheets almost at the same speed as the output speed of the image formation machine. High speed rollers located behind the infeed rollers which have a sheet feeding speed higher than that of the aforementioned infeed rollers, and to cause the infeed rollers to move along with the sheets when the transporting speed of the sheet surpasses the infeed speed of the infeed rollers occurs.
In the aforementioned post processor, the sheets sent by the infeed rollers are put between the high speed rollers and forcefully pulled in when the sheets reach the high speed rollers. On the other hand, since the infeed rollers are equipped with the one way clutch mechanism, the transporting speed of the sheets that are fed by the high speed rollers surpasses the sending speed of the infeed rollers occurs, and the infeed rollers change speed to move along with the sheets.
The structure of the high speed rollers should have two power rollers facing each other. By doing so, the high speed rollers can send the sheet assuredly.